Luís Sousa

Universidade de Trás-os-Montes e Alto Douro (UTAD), Departamento de Geologia, Faculty Member

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Address: Vila Real, Vila Real, Portugal

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Publicação de um roteiro geológico em plataforma WebSIG

VIII CNG 2010, 2010

Publishing a geological field trip using a WEBGIS platform J. LOURENÇO [email protected] (RESUMO:... more Publishing a geological field trip using a WEBGIS platform J. LOURENÇO [email protected] (RESUMO: O presente trabalho trata da publicação de um roteiro geológico na Web, através de um servidor WebSIG, de um percurso localizado na Serra do Alvão. Com esta publicação pretende-se disponibilizar a informação geológica recolhida, para possibilitar a realização de visitas de estudo virtuais e apoiar a aprendizagem e a divulgação de informação de carácter geológico. A plataforma WebSIG permitirá não só o acesso à informação representada nos mapas, com auxílio de ferramentas adequadas, mas também o acesso a páginas Web onde se disponibiliza informação complementar, como fotos, textos e links.

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Comparação Da Fracturação Em Pedreiras De Granito Ornamental

VIII CNG 2010, 2010

Page 1. e-Terra http://e-terra.geopor.pt ISSN 1645-0388 Volume 20 nº 14 2010 Revista Electrónic... more

Avaliação Da Cor, Brilho E Rugosidade Em Granitos Polidos

VIII CNG 2010, 2010

Page 1. e-Terra http://e-terra.geopor.pt ISSN 1645-0388 Volume 20 nº 16 2010 Revista Electrónic... more

Emissao acústica em granitos solicitados por incrementos de temperatura

by Luís Sousa and Luis Miguel Suarez Rio

$Research paper thumbnail of A influência da fracturaçao de rochas ornamentais: o caso do granito de Pedras Salgadas (Vila Real, Norte de Portugal)$

A influência da fracturaçao de rochas ornamentais: o caso do granito de Pedras Salgadas (Vila Real, Norte de Portugal)

Composição e Caracterização Cromática de Argamassas de Reparação para Painéis de Fachada em Betão Arquitetónico

Influence of the Microfissuration on the Physico-Mechanical Properties of Ornamental Granites

by Luís Sousa and Luis Miguel Suarez Rio

Nine granites from the North of Portugal were studied and some physical and mechanical properties... more Nine granites from the North of Portugal were studied and some physical and mechanical properties (open porosity, uniaxial compressive strength and velocity of compressional waves) were measured. The relationship between these properties was studied and the linear crack density of the granites was also determined to evaluate the influence of natural cracking on their physico-mechanical properties. In this kind of rocks, the voids are mainly in the form of microfissures and a good correlation between the open porosity and the linear crack density was found. The uniaxial compressive strength and the velocity of compressional waves decrease as the linear crack density increases, since the presence of fissures favours the rock failure and makes difficult the propagation of the seismic energy.

format_quotePedras Salgadas granite exhibits the highest uniaxial compressive strength at 197.0 MPa, while Águas Santas granite has a low strength of 62.4 MPa due to weathering.format_quote

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$Research paper thumbnail of Avaliação da densidade de fracturação nas pedreiras do granito de Mondim de Basto$

Avaliação da densidade de fracturação nas pedreiras do granito de Mondim de Basto

Page 1. e-Terra http://e-terra.geopor.pt ISSN 1645-0388 Volume 20 nº 15 2010 Revista Electrónic... more

$Research paper thumbnail of A influência da fracturação na exploração de rochas ornamentais: o caso do granito de Pedras Salgadas (Vila Real, Norte de Portugal)$

A influência da fracturação na exploração de rochas ornamentais: o caso do granito de Pedras Salgadas (Vila Real, Norte de Portugal)

Evaluation of the microfissuration in granites with different petrographical characteristics

The fissure typology of nine medium to coarse grained granites with different degrees of weatheri... more The fissure typology of nine medium to coarse grained granites with different degrees of weathering was studied. The observation under scanning electron microscopy allows the identification of the type of fissures (intergranular, intragranular and transgranular ones). Based upon the collected data, a fissuration index, called linear crack density, defined by the number of fissures per length unit, was calculated. The results show that the intragranular fissures are the most frequent ones, representing between 62.9% and 82.3% of the total of observed fissures. The intragranular fissures in feldspars correspond, in general, to more than a half of these fissures. The intergranular fissures tend to be located in the quartzfeldspars boundaries and represent less than 1/3 of the fissures. Based upon the linear crack density values a classification of the weathering degree of the studied granites is presented.

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Recognising the value of geoparks in promoting health: An interdisciplinary approach

by Luís Sousa, Elisabete Melo-Gomes, and Edna Cabecinha

$Research paper thumbnail of Assessing fracturing in weathered granites: The example of the mondim de basto granite (Northern Portugal)$

Assessing fracturing in weathered granites: The example of the mondim de basto granite (Northern Portugal)

Key Engineering Materials, 2013

Fracturing is the most limiting factor in the extraction of large blocks of granite for gang saw ... more Fracturing is the most limiting factor in the extraction of large blocks of granite for gang saw processing and should be carefully studied in the exploration stage. This paper presents the results of the fracturing evaluation of the granite from the quarries of Mondim de Basto, located in the north of Portugal. This very weathered granite has a high market demand and its commercial value is controlled by its yellowish brown colour. The fracturing was evaluated based on the mean/median joint spacing, as well as the volumetric joint count. The results stress the difficulty in obtaining large blocks since few places have the appropriate degree of jointing.

format_quoteFracturing controlled by two primary joint sets (N-S and E-W), demonstrating non-uniformity in granite quality across the region.format_quote

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Evaluation of the Portuguese Ornamental Stone Resources

Key Engineering Materials, 2013

Portugal produces a great diversity of ornamental stones. Besides the internationally known white... more Portugal produces a great diversity of ornamental stones. Besides the internationally known white and pink marbles, also light cream limestones are produced, as well as grey, yellow and pink granites, and dark grey slates. A first exercise is presented on the evaluation of the available resources of ornamental stones in the whole Portuguese territory. The results show a total availability of 410 million cubic meters, of which 274 million refer to granite, 76 million to limestone, 51 million to marble, and 9 million to slate.

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Dados preliminares da radioactividade natural na região de Amarante (Norte de Portugal)

Book of Abstracts Colours 2015: Innovative and Sustainable Technical Art Examination and Color Documentation

by Antonino Cosentino, Claudia Pelosi, graziella roselli, Pedro Alves, Luís Sousa, Emanuela Grifoni, and Katelin Fallon

Scientific examination and documentation of art is expensive. The most important and recognizable... more Scientific examination and documentation of art is expensive. The most important and recognizable
works of art from prestigious museums get extensive scientific studies, unfeasible for the vast
majority of cultural heritage objects, existing in local communities since they lack comparable
financial resources. Typically larger museums have budgets sufficient for scientific departments
equipped with cutting-edge technologies. In contrast, small to medium sized cultural institutions
have relatively limited access to the same science and technology.
Cultural Heritage Science Open Source (CHSOS) was launched in 2012 to bridge this technological
divide, to develop and disseminate affordable and sustainable methodologies for art examination
that can reach a much larger audience of cultural institutions. CHSOS disseminates methods for art
examination in three significant ways, focusing specifically on the low-cost technical solutions: its
popular blog, publications and training programs. The CHSOS blog has attracted a growing network
of art conservation professionals interested in introducing Cultural Heritage Science concepts into
their workflow.
CHSOS has developed and disseminated low-cost technical solutions for panoramic infrared
reflectography [1], technical photography [2,3], reflectance transformation imaging [4] and
reflectance spectroscopy [5]. This paper discusses the development of a low-cost multispectral
imaging [6] system for art and archaeology realized thanks to the first ever crowdfunding project
in art conservation science.

$Tne obtained results evidence a clear similarity in the pastes or the pottery produced at Vila Nova and some of the ceramic pastes from Lisbon, in accordance with documental sources that described the use of Lisbon clays by Vila Nova potters, at least since mid 17 century. Quartz and Gehlenite are the main components of these Lisbon’s pastes, but other different ceramic pastes were also detected pointing to the use of different clay sources. The spectroscopic trend exhibited in Coimbra’s pottery is remarkably different, Quartz and Diopside being the two major components of these pastes, enabling one to well define a pattern for these ceramic bodies. The blue pigment from the Lisbon samples is a cobalt oxide that exists in the silicate glassy matrix allowing the formation of detectable cobalt silicate microcrystals in most productions of the second half of the 17 century. A less clear micro-Raman cobalt blue signature was detected in the Vila Nova and Coimbra blue glazes, in accordance with lower kiln temperatures in these two production centres, the Co2+ ions being dispersed in the silicate matrix [1-3]. In all cases the white Sherds representative of the 17 century three main Portuguese faience production centres - Lisbon, Coimbra and Vila Nova were studied with the use of non-invasive spectroscopies, namely: micro-Raman, Ground State Diffuse Reflectance Absorption (GSDR), Fourier-Transform Infrared (FT-IR) and Proton Induced X-Ray (PIXE) or X-Ray Fluorescence Emission (XRF). X-Ray Diffraction (XRD) experiments were also performed.$

$The methodology includes historical study: iconography, photography, models and other sources. Colorimetric analysis determining the L * a* b * coordinates, contact spectrophotometer and image analysis compared with NCS color chart. The study was completed with the determination of the physicochemical properties of the coating materials: diffraction and X-ray fluorescence, infrared spectroscopy, optical microscopy and scanning electron microscopy. Figure 1. Visual analysis of layers of color. Tambour of the dome and facade of the Royal Ordnance Factory of Seville$

$1] A Brandmair B., Greiner S.P., ROhrmann J., Stradivari Varnish: Scientific Analysis of His Finishing Technique n Selected Instruments, 2010, Serving Audio Editore. JV fluorescence photography is widely used in the study of artworks, in particular for the analysi: of historical musical instruments (e.g. violins). This technique allows seeing important details whict cannot be observed with visible light, such as retouching, different paints coats or worn areas 01 ‘he superficial varnishes. However, interpretation of UV photos may be very complex and is strictly ‘elated to the preservation state: the more alterations, the wider range of colors that are detectec oy the technique. Recent studies on Stradivari violins have shown four main layers of materials or ‘he surface of the instruments: wood, wood filler, transparent paint coat and colored paint coat [1] The aim of this work is the development of a new tool able to automatically detect the presence of colours related to the worn areas on the back plates of violins. The study was performed on U\ mages of Stradivari violins of the historical collection held in the “Museo del Violino” in Cremona. Although paint coats of the examined instruments display considerably different colours, the analysis of the acquired data shows that all the worn areas (where the wood and the wood filler are more evident) are always characterised by the same colour hue, with a different level o7 saturation directly proportional to the level of wear. The system developed in the present worl “an automatically select these surface areas analysing the histogram of the images in HSV colour space. Our algorithm works even when worn areas cannot be directly detected by looking at the original photos due to perception illusion (e.g. very low level of wear and/or worn areas hidden by 1earest paint coats). During the computation, the fraction of the worn areas respect to the entire surface of the back plate is also computed. The detected areas are highlighted with three different evels of wear: high in red, medium in orange, low in yellow (see Figure 1).$

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How to determine the appropriate methods to identify the geometry of in situ rock blocks in dimension stones

by Reza Yarahmadi, Sayed-ghahreman Taherian, and Luís Sousa

Environmental Earth Sciences, 2015

The present article reviews various methods for discontinuity and rock block survey. The variety ... more The present article reviews various methods for discontinuity and rock block survey. The variety of techniques to determine the shape and size distribution of the rock blocks were divided into index and modeling methods. The index methods calculate the average size of a rock block as a representative of the rock mass. These methods are simple, cheap and fast, but are associated with large errors because of the presence of the rock mass of rock blocks with different geometries. Hence, index methods are not recommended. In modeling techniques, discontinuity surveys try to model the rock mass realistically to determine the geometry of all blocks with different algorithms. These methods also have some defects in modeling the discontinuities and calculating the geometry of blocks. In order to perform an evaluation of all methods, six conditions were identified to determine the method for surveying rock blocks. The conditions include the ability to model random discontinuities and joint sets with specific dimensions, the inability to simulate discontinuities with statistical methods (the ability to study a discontinuity network separately), determining the geometry of all rock blocks, considering the dangling and isolated discontinuities, simplicity, and three-dimensionality. Based on the above requirements, a new approach is proposed to determine suitable methods for use in the evaluation of dimension stones. This new methodology was applied in a limestone quarry in Joshqan, Iran, to verify the applicability of the different methods in dimension stone quarries.

How to determine the appropriate methods to identify the geometry of in situ rock blocks in dimension stones

by Luís Sousa and Sayed-ghahreman Taherian

The present article reviews various methods for discontinuity and rock block survey. The variety... more The present article reviews various methods for
discontinuity and rock block survey. The variety of techniques
to determine the shape and size distribution of the
rock blocks were divided into index and modeling methods.
The index methods calculate the average size of a rock
block as a representative of the rock mass. These methods
are simple, cheap and fast, but are associated with large
errors because of the presence of the rock mass of rock
blocks with different geometries. Hence, index methods are
not recommended. In modeling techniques, discontinuity
surveys try to model the rock mass realistically to determine
the geometry of all blocks with different algorithms.
These methods also have some defects in modeling the
discontinuities and calculating the geometry of blocks. In
order to perform an evaluation of all methods, six conditions
were identified to determine the method for surveying
rock blocks. The conditions include the ability to model
random discontinuities and joint sets with specific dimensions,
the inability to simulate discontinuities with statistical
methods (the ability to study a discontinuity network
separately), determining the geometry of all rock blocks,
considering the dangling and isolated discontinuities,
simplicity, and three-dimensionality. Based on the above
requirements, a new approach is proposed to determine
suitable methods for use in the evaluation of dimension
stones. This new methodology was applied in a limestone
quarry in Joshqan, Iran, to verify the applicability of the
different methods in dimension stone quarries.

format_quoteThe discussed methods help quarry owners and engineers select appropriate techniques for studying rock block geometry.format_quote

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Petrophysical properties and durability of granites employed as building stone: a comprehensive evaluation

Bulletin of Engineering Geology and the Environment , 2014

The use of a rock as a building stone is conditioned by several factors, from its aesthetic chara... more The use of a rock as a building stone is conditioned by several factors, from its aesthetic characteristics to its petrophysical properties. Even though the latter are taken into consideration, only a few of them are usually assessed. The purpose of this study is to carry out a comprehensive evaluation of the petrophysical properties of nine Portuguese granites employed as dimension stones. Granites with different textural characteristics and degrees of weathering were selected in order to highlight the relationships between the properties, and to identify the most important ones affecting the rock behaviour. The post-tectonic granites, with low porosity and fewer fissures, show better mechanical behaviour, while the most weathered granites have poor mechanical behaviour that limits their use in some applications and/or environmental conditions. L'utilisation d'une roche comme matériau de construction est conditionnée par plusieurs facteurs, soit les caractéristiques esthétiques ou les propriétés pétrophysiques. Même si ceux-ci sont pris en considération, seuls quelques-unes d'entre elles sont généralement évaluées. L’objectif de cette étude est de réaliser une évaluation complète des propriétés pétrophysiques de neuf granites portugais employés comme pierres de taille. Granites avec différentes textures et degrés d'altération ont été sélectionnés afin de mettre en évidence les relations entre les propriétés, et d'identifier les plus importantes qui conditionnent le comportement de la roche. Les granites post-tectoniques, avec une basse porosité et moins de fissures, présentent un meilleur comportement mécanique, tandis que les granites altérés ont plus mauvais comportement mécanique qui limitent leur utilisation en certaines applications et/ou des conditions environnementales.

$Fig. 5 Plot of water content versus square root of time of soaking Sound granites have a high UCS and the Pedras Salgadas granite, with a UCS of 197.0 MPa, stands out from the other sound granites (Chaves and Teloes granites). The smaller grain size of the Pedras Salgadas granite and the heterogeneous nature of the other two granites (see Table 3) may explain this difference, since larger grains fracture at lower stresses than finer grains and the textural fracture at lower stresses than finer grains and the textura the deformation is a plastic-elastic—plastic type. The distinctive mechanical behaviour of the granites studied can be verified both in the stress—strain curves and in the acoustic emission pattern. The two plots in Fig. 2 characterize granite groups with a different behaviours. These granites show stress—strain curves typical of the crystalline rocks when subjected to uniaxial compression (Gupta and Rao 2000). The sound rocks have an elastic— plastic behaviour, like the Pedras Salgadas granite. In the sound granites (PS, CH and TE) the plastic portion of the stress-strain curve begins at 90 % of UCS. The Aguas Santas granite has a significant initial and final deforma- tion, with a sigmoid-shaped curve, due to the closing of pre-existing microcracks (Seo et al. 2002), while the other granites have a small or no initial deformation. In general, the deformation is a plastic-elastic—plastic type.$

$Fig. 18 Dendogram using average linkage (between groups) (employed properties: Eqsize; ya; no; W UCS; MT; E,; LCD; Vp;SHR¢s, AVpct; AVpts125; AVpft419) Contrary to expectations, since the frost action tends to fracture the rocks, Vp values increased slowly during the test. This situation was described by Ortiz (1996) in a similar test (with a 12-h cycle) with Vp values showing irregular changes. Azzoni et al. (1992) observed a 9.7 % increase in Vp after 321 cycles, similar to the one carried out in this study. The explanation for these results could be in the cycle timing, which was not long enough to allow complete thawing inside the samples. For verification, the samples were dried in an oven before determining the Vp at cycles 291 and 419. The results show a decrease in Vp from 3 %, in the Pedras Salgadas granite, to 12 %, in the Aguas Santas granite, and the variation is not significant between cycles 291 and 419 (Table 5). Antéo and Rodrigues (2000) describe a Vp decrease of 10 % in low porosity granites after 460 cycles within a 13.45-h period. The Aguas Santas$

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The influence of the characteristics of quartz and mineral deterioration on the strength of granitic dimensional stones

Environmental Earth Sciences, 2013

It is important to have a thorough knowledge of the petrographic characteristics of rocks to eval... more It is important to have a thorough knowledge of the petrographic characteristics of rocks to evaluate and understand their mechanical behavior. This paper deals with the influence of the texture and the mineral characteristics of nine Portuguese granites employed as dimensional stones. This study evaluates different mineral characteristics, such as mineral deterioration, grain size, quartz fissuration and the contacts between quartz and others mineral groups. The main differences in the studied granites were identified, clarifying the relationship between the petrographic characteristics. The consequences on their respective mechanical behavior were subsequently evaluated. The physical and textural characteristics of quartz in the studied granites have proven to be very important for understanding the behavior of granitic rocks under compressive stress. Uniaxial compressive strength values are not proportional to the quartz–feldspar ratio or quartz content and there is a tendency for strength to decrease with the increase in quartz. This could be related to the increase in quartz-quartz contacts and the decrease in the rock capacity for accommodating the deformation.

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Differences in the quality of polishing between sound and weathered granites

Environmental Earth Sciences, 2013

Aesthetic characteristics are important when rocks are used as construction materials. Among all ... more Aesthetic characteristics are important when rocks are used as construction materials. Among all the surface finishes available, the polished finish is the one which best enhances the rock attractiveness. Colour (C), roughness (R) and gloss (G) are surface properties usually used to assess the rock polishing. In this research, the CRG properties were assessed in polished samples of three ornamental granites with different textures and physical–mechanical properties, one weathered and two sound. C was evaluated in CIE-L * a * b * and CIE-L * C * ab h ab systems, R with R a and R z parameters and G using the 20°, 60° and 85° geometries. The weathered granite presents a noticeable colour variation, especially in the b * parameter, while the sound ones have a more homogeneous colour. Sound and more textural homogeneous granites have a low surface roughness and high gloss, which are uniformly distributed. The weathered granite shows a higher surface roughness and lower gloss, with scattered distribution. The mineral contacts are the main cause of the surface irregularities. The results show the interdependence between the CRG properties and stress the importance of the polishing process for enhancing the aesthetic characteristics of the granites. CRG properties could be used for quality control in granite processing plants, thus avoiding noticeable differences in the facades of buildings, particularly when weathered granites are used.

format_quoteRoughness ranges from 0.7 to 4.3 µm (R a), with weathered granite showing greater variability, influenced by mineral types and weathering.format_quote

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Luís Sousa

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